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Title: A pilot assessment of alpha-stat vs pH-stat arterial blood gas analysis after cardiac arrest.
Authors: Eastwood, Glenn M;Suzuki, Satoshi;Lluch, Cristina;Schneider, Antoine G;Bellomo, Rinaldo
Affiliation: School of Nursing and Midwifery, Deakin University, Melbourne, Australia; Department of Intensive Care, Austin Hospital, Victoria, Melbourne, Australia. Electronic address:
Department of Anesthesiology and Resuscitology, Okayama University Hospital, Okayama, Japan. Electronic address:
Department of Intensive Care, Hospital Universitari Mutua Terrassa, Barcelona, Spain. Electronic address:
Department of Intensive Care Medicine and Burn Center, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. Electronic address:
Department of Intensive Care, Austin Hospital, Victoria, Melbourne, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia. Electronic address:
Issue Date: 2-Oct-2014
Citation: Journal of Critical Care 2014; 30(1): 138-44
Abstract: Resuscitated cardiac arrest (CA) patients typically receive therapeutic hypothermia, but arterial blood gases (ABGs) are often assessed after adjustment to 37°C (alpha-stat) instead of actual body temperature (pH-stat). We sought to compare alpha-stat and pH-stat assessment of PaO2 and PaCO2 in such patients.Using ABG data obtained during the first 24 hours of intensive care unit admission, we determined the impact of measured alpha vs calculated pH-stat on PaO2 and PaCO2 on patient classification and outcomes for CA patients.We assessed 1013 ABGs from 120 CA patients with a median age of patients 66 years (interquartile range, 50-76). Median alpha-stat PaO2 changed from 122 (95-156) to 107 (82-143) mm Hg with pH-stat and median PaCO2 from 39 (34-46) to 35 (30-41) mm Hg (both P < .001). Using the categories of hyperoxemia, normoxemia, and hypoxemia, pH-stat estimation of PaO2 reclassified approximately 20% of patients. Using the categories of hypercapnia, normocapnia, and hypocapnia, pH stat estimation of PaCO2 reclassified approximately 40% of patients. The mortality of patients in different PaO2 and PaCO2 categories was similar for pH-stat and alpha-stat.Using the pH-stat method, fewer resuscitated CA patients admitted to intensive care unit were classified as hyperoxemic or hypercapnic compared with alpha-stat. These findings suggest an impact of ABG assessment methodology on PaO2, PaCO2 , and patient classification but not on associated outcomes.
Internal ID Number: 25449882
DOI: 10.1016/j.jcrc.2014.09.022
Type: Journal Article
Subjects: Arterial blood gas
Cardiac arrest
Intensive care
Blood Gas Analysis
Body Temperature
Heart Arrest.blood.mortality
Hypothermia, Induced
Intensive Care Units
Middle Aged
Pilot Projects
Retrospective Studies
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